56 PLANT MIGRATION 
wind, or passing animals, bending the stem, cause the 
latter to spring back, casting the seeds out. When 
the seed-vessel opens widely, as in the Columbine 
(Aquilegia), the seeds may be cast to some small 
distance. The efficacy of the arrangement is not so 
obvious when, as in the Poppies (Papaver) or Bell- 
Fic. 8.—Frvit oF GIANT BELL-FLOWER (CAMPANULA 
LATIFOLIA). . 
flowers (Campanula), the openings are small (Fig. 8), 
but it is clear that these plants do not suffer from 
lack of dispersal, in view of their abundance and wide 
range. 
But the assistance which the parent plant gives is 
often of a more active and even dramatic character, 
though in these cases it is usually effected not by a 
